Exhaust air filtration & heat recovery for stenter frames
Clean air. Save energy.
In textile finishing processes exhaust air purification can be seen as a particular challenge. Especially exhaust air caused by the application of stenter frames requires a highly efficient separation since the emerging smoky waste air is odor-intensive and made up of wax, oil and fibre particles. Depending on the production location textile producers are faced with strict regulations in terms of emission limits for stenter frames.
Energy costs account for a large share of production costs
The application of stenter frames is in the field of textile finishing for fabric heat treatment (woven to knitted fabrics) where the fabric is not only dried but also subject to thermo-fixation.
The operating temperature can be up to more than 200°C depending on the actual production mode and fabric. For its operation the stenter requires a high consumption of electrical energy (e.g. for motors and ventilators) as well as a high consumption of heat – as intake for the cost intensive gas and thermal oil heating.
When faced with polluted exhaust air derived from a stenter an unsuitable filter cell would wear out rapidly and entail high cost for filter exchange or replacement. In addition to that the exhaust air of the stenter frame contains valuable heat which can be utilised for subsequent processes.
KMA Filter are suitable for all kind of textile fabrics which are processed in a stenter frame:
- natural fibers: wool, cotton
- synthetic fibres: polyacrylic, polyamide, polyester
- natural chemical fibres: viscose/ acetate
With the ULTRAVENT® exhaust air filter system KMA Umwelttechnik delivers an economical and energy efficient solution for stenter frame exhaust air purification.
KMA is pursuing three objectives:
1. Achievement of clean gas values
The exhaust air is profoundly purified by the KMA electrical filter cells before being led into the atmosphere, to avoid nuisances and the emission of pollutants. The exhaust emissions of the production facilities are diminished and external nuisance resulting from air pollution is eliminated.
The strict European provisions and regulations serve as benchmark for minimised emission limits.
2. Reduction of energy costs
By means of the integrated heat recovery system the exhaust heat is efficiently recuperated for the utilization in subsequent processes.
The heat derived from the hot exhaust air can be utilized for the supply air heating which is feeding the stenter frame. Through this efficient heat recovery the operating costs of the stenter frame can be radically reduced due to lower expenses for the conventional heat supply (expensive gas and thermal oil heating). At the same time the recovered heat can be utilized for water heating employed in other production areas (dye house or laundry).
3. Long service life and low maintenance
The KMA exhaust air filter system operated with an integrated cleaning system. The automatic filter cleaning system allows for a regular cleaning of the filter modules while ensuring the full effectiveness of the filter and heat recovery modules.
Less energy consumption means less costs.
Save up to 80% of your energy costs!
Less energy consumption means less costs.
KMA filter use the valuable heat out of the extract air and reduce the energy consumption of your production facility by means of heat recovery.
How to lower the energy costs of your stenter frame is explained in the following case study.
Filter sizes and modules
KMA ULTRAVENT® systems are available in three sizes with a filter exhaust air capacity of 15,000, 20,000 and 30,000 m³/h. For larger exhaust air volumes two or more KMA systems can be easily connected to each other.
The KMA exhaust air systems are assembled on a modular system, which combines several system´s components.Therefore ULTRAVENT® system allows a precise adaptation to the needs of the stenter. According to the customer´s request each system can be equipped with several heat exchanger modules. Thus, a KMA exhaust air system with three heat exchanger modules and two electrostatic filter stages is a common example.
Heat recovery for the heating of air & water
With the energy saving KMA system the recovered heat can be utilized to heat up supply air and process water. As a result, the overall energy consumption of the stenter is reduced, since less energy from the cost intensive conventional heating methods such as gas or thermal oil heating is required.
KMA exhaust air filter are equipped with electrostatic filter cells for particle separation, heat exchangers for heat recovery, an automatic cleaning system for the cleaning of the filter modules and optionally additional filter elements as UV-lights, activated carbon or scrubber.
Individual solutions for a wide variety of requirements in the textile industry
Depending on the application, KMA ULTRAVENT® exhaust air purification systems can be equipped with different modules for the separation of smoke and aerosols and for the recovery of process heat.
Pre-filtration is essential when processing rough fabrics made of coarse woven fibers. KMA offers a lint filter for this purpose. It consists of stable stainless steel meshes. The special rolling of the wire enables high separation efficiency with coarse dust particles.
The cells can be cleaned by washing. An exchange of the demister cells is not necessary.
Fume separation and oil recovery
ULTRAVENT® electrostatic precipitator cells allow for a high degree of separation of smoke, dust and fine mist. The filter cells are characterized by their robust construction:
Stainless steel frames and support rods, oil-resistant ceramic insulators and a filter design optimized for the separation of liquid and viscous substances make the electrostatic precipitator an extremely economical and durable filter medium. The oil released during the process can be recovered and reused due to the special construction of the electrostatic precipitator cell.
Energy-saving heat recovery system
The integration of heat exchangers in the ULTRAVENT® filter system enables the recovery of process heat in addition to the purification of exhaust air. The heat extracted from the exhaust air is available for heating of subsequent processes (e.g. water or supply air heating). Depending on the application, either air-air or air-water heat exchangers are used.
For particularly strong odors, which can be caused by chemicals or textiles used in the thermofixing process, KMA offers a separate UV light module for odour separation. With UV light many intensive smelling VOC molecules can be oxidized. The result is a significant improvement of the odor situation, in many cases odors are completely eliminated. Like activated carbon, UV light requires good pre-separation of dust or smoke in order to be fully effective in the long term. Following a UV oxidation stage, a reaction line is always necessary to complete the oxidation process.
The KMA filter system features an automatic module waxing system. It allows regular and labor-saving cleaning of electrostatic filter cells, UV light tubes and heat exchanger modules, thus ensuring minimum maintenance.
Unmatched in terms of comfort and washing results
The automatic cleaning system works like a custom-made integrated dishwasher thanks to its movable nozzle block, which is moved back and forth between the individual modules during the washing process. It allows regular and labor-saving cleaning of the filter cells and thus ensures minimum maintenance. The intelligent control of the cleaning process also reduces the consumption of washing water and detergent.
The oil collected in the washing tank is drained off via a condensate drain and can thus be recovered, reused or sold.
KMA ULTRAVENT® filters are characterized by the following features:
- Cost-effective operation through wear-resistant filters and low energy consumption
- Minimised maintenance due to highly effective automatic filter cleaning
- Flexibility through a modular system with many different sizes
- Durability: filter housing and collection cells are made of stainless steel or aluminium
Due to the wide choice of filter media the KMA ULTRAVENT® System is very flexibly to use and is also suitable for high filter loading.
The KMA ULTRAVENT® exhaust system allows the highly efficient collection and separation of emissions like mist from release agents, oil mist, wax particles, plasticizer fumes, and emulsion mist. Due to the special filter design liquid components (oil, emulsion, etc.) get discharged during operation. Adhesive substances can easily be removed by the optional automatic filter cleaning system.